Art of laminating glass



Patented Sept. 3, 1935 UNITED STATES ART OF LAMINATING GLASS August W. Hornig, Chicago, Ill.

No Drawing. Application September 26, 1930,

Serial No. 484,715

7 Claims.

The type of laminated glass with which my invention is concerned, is that in which a sheet of celluloid is interposed between sheets of glass. It should be understood that in using the term celluloid I include all equivalent preparations or materials.

The object of my invention is the same as the one set forth in my application for United States Letters Patent, filed March 16, 1929, Ser. No. 347,727. In fact, the present'invention constitutes but a modification; in several particulars, of the process described in that application.

I have found that the process there described can, to advantage, be modified in the following particulars A, I apply to the celluloid sheets to be used in the laminating of the glass plates, in lieu of the pure distillate from a suitable mineral amyl alcohol described in my said prior application, an amyl chloride or amylene dichloride, or mixed amyl chlorides, or, preferably, mixed amylene dichlorides, using these chlorides preferably mixed with a distillate from a suitable mineral amyl alcohol, such as pentasol, in a proportion of about chloride and 25% distillate. Neither the above mentioned chlorides alone nor their mixtures with a distillate from mineral amyl alcohol in the proportions indicated, are solvents of celluloid,--not even at boiling temperatures continued for several hours: but their application yields excellent results in lamination when used in accordance .with my method. I prefer to use the chlorides mixed with a distillate from a suitable mineral amyl alcohol particularly when the celluloid to be used has become somewhat stiff and brittle, because the distillate has a tendency to mitigate this stiffness and brittleness. On the other hand the predominant use of the chlorides prevents bubbling, and reduces to a minimum discoloration of the celluloid on exposure to hot sunlight. I prefer to apply my preparation by wash? ing of the celluloid rather than by dipping the celluloid into it. v

B. Instead of using the padded tray and frame described in my application for 'United States Letters Patent, Ser. No. 345,520, filed March 8, 1929, I prefer to use the corrugated baseplate and hinged stops described in my application for United States Patent, Ser. No. 469,207, filed July 19, 1930, covered with a sheet of wet muslin and, on top of that, two sheets of water soaked strawboard paper, which in turn are covered with a sheet of muslin. On top of this sheet of muslin I place, against the faces of the hinged stops, the glassplates to be laminated, preferably prepared as above described, with a celluloid sheet interposed between them, also preferably prepared as above described. To secure absolute cleanness and lucidity of the glassplates I prefer to wash them, immediately before the celluloid is placed 5 between them, with the same preparation, described under A above, with which the celluloid is washed. I then place upon the top glassplate a sheet of strawboard, soaked with a suitable oil, preferably mineral lubricating oil, place on top of such oiled strawboard two sheets of strawboard, soaked in water, preferably cold, and place on top of these sheets a sheet of wet fabric, such as muslin. All of the strawboard sheets used in this process are of a thickness of about 0.03" each. The corrugated baseplate, with the materials thus assembled thereon, I place upon the lower platen of apress, both platens of which are heated to a sustained temperature of 250 to 500 Fahrenheit, and immediately, and as quickly as possible, apply a pressure ranging from about 30 to 50 pounds per square inch for a period ranging from 2 to 10 minutes, according to the heat of the press and the thickness of the glass sheets to be laminated. When I release the press, the top muslin sheet will adhere to the upper platen of it, by reason of the sticky substance squeezed out of the wet strawboard on which it was placed. The corrugated baseplate, with the remaining materials thereon, is then pulled out of the press, prefer- 30 ably onto a table; the strawboard sheets used are discarded; the laminated glassplates, with the celluloid between, are removed and placed upon a flat horizontal surface until they are cooled, and the muslin sheet placed below the glass sheets is removed to be used again until worn out, while the muslin sheet that was placed upon the corrugated baseplate. will adhere thereto for the same reason that the upper muslin sheet will adhere to the upper platen of the press. I then "40 place the corrugated baseplate with the muslin sheet adhering .therete into cold running water for the purpose of cooling it quickly, and then assemble on it like materials as above set forth, except that the muslin sheets have to be thoroughly washed after they have been used for laminating about twenty-five sets of glassplates. While it is practicable to use the strawboard sheets likewise repeatedly, I have come to the conclusion that breakage is moresafely avoided 59 by using new strawboard sheets for each lamination. The muslin sheets are inserted to prevent the water-wet strawboard sheets from sticking to the metal and glass surfaces, which otherwise they would directly adjoin. In thisrespect, as 55 to the upper glassplate, the oil soaked strawboard fulfills the same function as a muslin sheet would. But the main purpose of inserting an oil soaked strawboard sheet at the place described, is the development of steam and steam pressure on top of the glassplates while the platens of the press exert their maximum pressure and while the glassplates are heated to maximum heat. Observation and experience have demonstrated that before this point is reached, all water steam generated from water-wet strawboard sheets inserted in the press is driven off by the heat of the platens. But when an oil soaked sheet is interposed, a puff of oilsteam always issues from between the platens when their pressure is released on completion of the lamination. This indicates the presence of oilsteam between the platens at the very time when lamination is completed under maximum heat,-insuring equalization of pressure over the entire surface to be laminated. The reason why I insert the oil soaked strawboard sheet above the glassplates, and not below them,

is that any steam generated below the glassplates would escape through the corrugations of the baseplate described in my application for United States Patent, Ser. No. 469,207. It is to be noted that the use of either water soaked or oil soaked strawboard sheets will aid in the attainment of superior lamination. But the combined use of water soaked sheets and at least one oil soaked sheet is preferable because the use of oil soaked sheets alone would be more expensive and would cause more disagreeable odors and smoke, while the use of water soaked sheets alone would give less perfect results. It is also to be noted that I prefer to place the oil soaked sheet next to the glassplates because that saves an extra muslin sheet; also because by placing it there less steam and smoke is developed from the oil than there would be if the oil soaked sheet were placed directly beneath the hot upper platen, and finally because it is advantageous to have the oilsteam developed notv at the beginning, but rather. at the end of the laminating process.

C. I omit the secondary heating described in my prior application (Ser. No. 347,727, filed March 16, 1929). I find it unnecessary to use it, where I treat the celluloid with chlorides as hereinabove described.

It is manifest that my process may be deviated from, or altered, in many details without departing from the essential features of my invention. All such deviations or alterations I intend to cover by my claims.

I claim 1. A process of producing laminated glass, comprising the application, preliminary to the use of pressure and heat, of amylene dichloride to a celluloid sheet to be used in lamination.

2. A process of producing laminated glass, comprising the application, preliminary to the use of pressure and heat, of amylene dichloride, mixed with a distillate from mineral amyl alcohol, to a celluloid sheet to be used in lamination.

3. A process of producing laminated glass, comprising the application, preliminary to the use of pressure and heat, of amylene dichloride, mixed with a distillate from pentasol, to a celluloid sheet to be used in lamination.

4. A process of producing laminated glass, comprising the step of placing of the materials to be laminated between wet sheets, at least one of said sheets being soaked with oil, preliminary to the application of pressure and heat.

5. A process of producing laminated glass, comprising the step of placing of the materials to be laminated between wet sheets, at least one of said sheets being soaked with oil, and being placed next to one of the glassplates, preliminary to the application of pressure and heat.

6. A process of producing laminated glass, comprising the step of placing of the materials to be laminated between wet sheets upon a corrugated tray, at least one of said sheets being soaked with oil and placed above the glassplates, preliminary to the application of pressure and heat.

7. A process of producing laminated glass, comprising the step of placing of the materials to be laminated between wet sheets upon a corrugated tray, at least one of said sheets being soaked with oil and placed above and next to the upper glassplate, preliminary to the application of pressure and heat.

AUGUST W. HORNIG. 

